approach unnoticed

At least this way he could approach unnoticed.

The noise of the wind and waves drowned their footsteps, and they were able to approach unnoticed till they were within a few feet of the lovers.

At such a time the bird sees very imperfectly, if at all, in fact he seems so preoccupied that if pursued one may often approach unnoticed.

Thompson and some others lifted Huntington, and carried him into the store; and at that moment the stage, its approach unnoticed, rattled up, and stopped with shrieking brakes and creaking harness.

On our left, their approach unnoticed by us in the fog, our infantry were marching in fours; from away to the south-west, as far as the eye could see, came three mighty columns of marching men, sunburnt, silent, inexorable.